Novel DNA methylation biomarkers for hexavalent chromium exposure: an epigenome-wide analysis.

Aim: We aimed to identify differential methylation of genes that could illuminate the biological mechanisms of chromium (VI) toxicity in this exposure-control study. Materials & methods: DNA methylation was measured in blood samples collected from electroplating workers and controls using a combination of Infinium Methylation 450K Chip and targeted-bisulfite sequencing. QuantiGene assay was used to detect the mRNA expression of differentially methylated genes. Inductively coupled plasma-mass spectrometry was used to quantify metals in blood and urine samples. The cytosine-phosphate-guanine sites methylation and gene expression were confirmed in a human lymphoblastoid cell line. Results & conclusion: A total of 131 differentially methylated cytosine-phosphate-guanine sites were found between exposures and controls. DNA methylation of SEMA4B may serve as a potential biomarker for chromium (VI) exposure.